Patent GB-658183-A (GB)
Title: Improvements in or relating to lubricating compositions
Inventor: EVANS ELLIOTT ALFRED
IPC: C10M137/10
Filed: 1947-12-09
Abstract: Tin petroleum sulphonate.-The tin salt of an oil-soluble petroleum sulphonic acid is used as an ingredient of a lubricating composition. In an example, an oil-concentrate containing sodium petroleum sulphonate derived from mahogany acids is dissolved in water.  Tin petroleum sulphonate is precipitated from the solution by adding stannous chloride solution.  Metal salts of organic dithiophosphoric acids.-Oil-soluble polyvalent metal salts of organic dithiophosphoric acids are used as ingredients of lubricating compositions, (see Group III).  The salts may be substances of the general formula <FORM:0658183/IV (b)/1> where n is the valency of the metal M, R1 is any suitable organic radicle and R2 is an alkylated aromatic radicle. R1 may be derived from an aliphatic alcohol such as butyl amyl or lauryl alcohol, a cyclic alcohol such as cyclohexanol or methylcyclohexanol, a phenol such as cresol or octyl cresol or an aromatic alcohol such as benzyl alcohol.  The radicle R2 may be derived from p-tert-amyl phenol, p-octyl phenol or octylcresol and preferably contains at least five carbon atoms in the alkyl group. However, the alkyl group of radicle R2 may contain less than five carbon atoms and may even be absent provided R1 is of such a nature as to confer oil-solubility upon the metal salt.  The salts may alternatively be substances of the same general formula as that given above but wherein R1 and R2 are alkyl or cyclo-alkyl groups having at least five and preferably not more than ten carbon atoms either in a straight or branched chain or ring.  Thus radicles R1 and R2 are preferably similar and may be derived from amyl alcohol, the hexyl alcohols such as n-hexyl alcohol, methyl isobutyl carbinol and 2 ethyl butanol, 2-ethyl hexanol, nonyl alcohol, cyclohexanol or methyl cyclohexanol.  Organic dithiophosphoric acids from which the salts may be derived are di-(octyl-cresyl)-dithiophosphoric acid, octyl-cresyl cresyl dithiophosphoric acid, octyl-cresyl 2-ethyl hexyl dithiophosphoric acid, di-(p-octyl phenyl)-dithiophosphoric acid, di - (tert - butyl cresyl) - dithiophosphoric acid, octyl cresyl n-butyl dithiophosphoric acid, octyl cresyl cyclohexyl dithiophosphoric acid, di-(n-hexyl)-dithiophosphoric acid, di-(2-ethyl hexyl)-dithiophosphoric acid, di-(methyl cyclohexyl)-dithiophosphoric acid, diamyl dithiophosphoric acid and di-(a -methyl isoamyl)-dithiophosphoric acid.  The octyl cresyl radicle mentioned in some of these acids is that derived from the mixture of octyl cresols obtained by alkylating cresylic acid with diisobutylene.  The salts may be salts of chromium, barium, calcium, strontium, magnesium, zinc, aluminium, nickel, cobalt, tin, cadmium or manganese, and they may be derived from a mixture of organic dithiophosphoric acids.  The acids may be prepared by reacting the appropriate organic hydroxy compounds with phosphorus pentasulphide. The salts may be prepared from the acids by direct neutralization with metal oxide or hydroxide or by metathesis from the sodium salt. In the examples: (1) chromium di-(octyl-cresyl)-dithiophosphate is prepared by reacting octyl cresol with P2S5, converting the acid obtained to its sodium salt and then precipitating the chromium salt by addition of chrome alum; (2) zinc di-(2-ethyl hexyl)-dithiophosphate is prepared by reacting 2-ethyl hexanol with P2S5 and neutralizing the acid obtained with zinc oxide; (3) tin octylcresyl 2-ethyl hexyl dithiophosphate is prepared by reacting a mixture of octyl cresol and 2-ethyl hexanol with P2S5, converting the acid obtained to its sodium salt, and then precipitating the tin salt with stannous chloride; (4) mixed chromium-zinc salt of di-(2-ethyl hexyl)-dithiophosphoric acid is prepared by reacting 2-ethyl hexanol with P2S5 and neutralizing the acid obtained with chromium hydroxide and zinc oxide; (5) chromium octyl-cresyl cresyl dithiophosphate is prepared by reacting a mixture of octyl cresol and cresylic acid with P2S5 and forming the chromium salt; (6) manganese di - (tert. - butyl cresyl) - dithiophosphate is prepared from a mixture of tert.-butyl cresols derived from cresylic acid, and (7) zinc di-(methyl cyclohexyl)-dithiophosphate is prepared from a mixture of methyl cyclohexanols obtained by the hydrogenation of cresylic acid. Reference has been directed by the Comptroller to Specifications 623,591 and 658,243.ALSO:A mineral lubricating oil composition suitable for use as the lubricant in petrol- or oil-operated internal-combustion engines comprises minor proportions of (a) the tin salt of an oil-soluble petroleum sulphonic acid and (b) an oil-soluble polyvalent metal salt of an organic dithiophosphoric acid.  The composition possesses detergent properties and any tendency of the mineral oil to form deleterious oxidation products, particularly products corrosive to metals, is inhibited.  The composition is particularly suitable for use as a heavy-duty lubricant in Diesel and other oil-operated engines.  Ingredient (b) may be a substance of the general formula <FORM:0658183/III/1> where n is the valency of a metal M, R1 is any suitable organic radicle and R2 is an alkylated aromatic radicle. R1 may be derived from an aliphatic alcohol such as butyl, amyl or lauryl alcohol, a cyclic alcohol such as cyclohexanol or methyl cyclohexanol, a phenol such as cresol or octyl cresol or an aromatic alcohol such as benzyl alcohol. The radicle R2 may be derived from p-tert.-amyl phenol, p-octyl phenol or octyl cresol and preferably contains at least five carbon atoms in the alkyl group.  However, the alkyl group of radicle R2 may contain less than five carbon atoms and may even be absent provided R1 is of such a nature as to confer oil-solubility upon the metal salt.  Ingredient (b) may alternatively be a substance of the same general formula as that given above but wherein R1 and R2 are alkyl or cyclo-alkyl groups having at least five and preferably not more than ten carbon atoms either in a straight or branched chain or ring. Thus radicles R1 and R2 are preferably similar and may be derived from amyl alcohol, the hexyl alcohols such as n-hexyl alcohol, methyl isobutyl carbinol and 2-ethyl butanol, 2-ethyl hexanol, nonyl alcohol, cyclohexanol or methyl cyclohexanol.  Organic dithiophosphoric acids from which ingredient (b) may be derived are di-(octyl-cresyl) dithiophosphoric acid, octyl-cresyl cresyl dithiophosphoric acid, octyl-cresyl 2-ethyl hexyl dithiophosphoric acid, di-(p-octyl phenyl) dithiophosphoric acid, di-(tert.-butyl cresyl) dithiophosphoric acid, octyl cresyl n-butyl dithiophosphoric acid, octyl cresyl cyclohexyl dithiophosphoric acid, di-(n-hexyl) dithiophosphoric acid, di-(2-ethyl hexyl) dithiophosphoric acid, di-(methyl cyclohexyl) dithiophosphoric acid, diamyl dithiophosphoric acid and di-(a -methyl isoamyl) dithiophosphoric acid.  The octyl cresyl radicle mentioned in some of these acids is that derived from the mixture of octyl cresols obtained by alkylating cresylic acid with di-isobutylene.  Ingredient (b) may be a salt of chromium, barium, calcium, strontium, magnesium, zinc, aluminium, nickel, cobalt, tin, cadmium or manganese and it may be derived from a mixture of organic dithiophosphoric acids.  Since ingredient (b) may be prepared from the free organic dithiophosphoric acid and since this may first be converted to the sodium salt and then the desired metal salt obtained by metathesis, ingredient (b) may be contaminated with free organic dithiophosphoric acids or their sodium salts.  The mineral lubricating oil composition may also contain as a third ingredient one or more of (1) a hydroxy-substituted aromatic thio-ether and/or di- or poly-sulphide, particularly di - (3 - carbomethoxy - 4 - hydroxyphenyl) thioether, disulphide or polysulphides; (2) an aromatic phosphite or thiophosphite ester derived from substance (1), particularly di-(3-carbomethoxy - 4 - hydroxyphenyl) thioether cresyl phosphite, and (3) a tri-aryl phosphite, particularly triphenyl phosphite or tri-(p-tert.-amyl phenyl) phosphite.  In the examples there are described mineral lubricating cil compositions containing tin mahogany sulphonate and one of the following metal salts of organic dithiophosphoric acids: zinc di-(a -methyl isoamyl) dithiophosphate, chromium or zinc di-(octyl cresyl) dithiophosphate, chromium or magnesium di-(2-ethyl hexyl) dithiophosphate, cobalt octyl cresyl n-butyl dithiophosphate, chromium di-(p-octyl phenyl) dithiophosphate, cadmium octyl-cresyl cyclohexyl dithiophosphate, nickel di-(methyl cyclohexyl) dithiophosphate, manganese di-(tert.-butyl cresyl) dithiophosphate, chromium, zinc or tin octyl cresyl 2-ethyl hexyl dithiophosphate, zinc di-(a -methyl isoamyl) dithiophosphate.  Other examples describe mineral lubricating oil compositions containing tin mahogany sulphonate and (i) zinc di-n-hexyl dithiophosphate and chromium octyl cresyl cresyl dithiophosphate; (ii) zinc di-(2-ethyl hexyl) dithiophosphate and tri-(p-tert.-amyl phenyl) phosphite; (iii) zinc di-(methyl cyclohexyl) dithiophosphate and octyl cresol thioether; (iv) zinc di-(a -methyl isoamyl) dithiophosphate and chromium di-(octyl cresyl) dithiophosphate with or without di-(3-carbomethoxy-4-hydroxy phenyl) thioether or di-(3-carbomethoxy-4-hydroxy phenyl) thioether cresyl phosphite; or (v) chromium di-(octyl cresyl) dithiophosphate with either di-(3-carbomethoxy-4-hydroxy phenyl) thioether cresyl phosphite or di-(3-carbomethoxy-4-hydroxy phenyl) polysulphide.  For comparison purposes mineral lubricating oil compositions are described which contain (1) tin mahogany sulphonate; (2) zinc di-(a -methyl isoamyl) dithiophosphate; or (3) chromium di-(octyl cresyl) dithiophosphate with or without sodium or calcium mahogany sulphonate. Specifications 561,898, 567,939, 574,445, 594,960, 658,182 and U.S.A. Specification 2,125,936 are referred to.  In the Provisional Specifications, Specifications 43